Those types of short term climate fluctuations do not have to be driven by ENSO, so are not sufficient to say that the atmosphere has coupled to the ocean across the equatorial Pacific.  We also look for changes in tropical rainfall and and sea level pressure (the Southern Oscillation Index) as well as changes in the winds across the Pacific.  During October, these parameters were normal, so not indicative of El Nino.  We will provide an updated assessment next week on December 13, and if the atmosphere shows signs of coupling to the warm ocean we will likely update the El Nino Watch to an El Nino Advisory.